[FEATURE] Exclude doktypes from pagetree

Exclude specific doktypes from the pagetree by setting
a configuration in a user/group TSconfig

Example: Exclude "Folder" pages
  options.pageTree.excludeDoktypes = 254

Example: Exclude "Folder" and "Standard" pages
  options.pageTree.excludeDoktypes = 254,1

Resolves: #49279
Releases: 6.2
Change-Id: I806c9892b07382ce424f656234b6992b349885f1
Reviewed-on: https://review.typo3.org/21520
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters